What is the meaning of the counter "Memory$\%$ Committed Bytes in Use"?

Question $40$Select one:

a$.$

The size, in bytes, of the non$-$paged pool, which contains objects that cannot be paged to the disk

b$.$

The amount of virtual memory currently available

c$.$

The number of entries in the page table not currently in use by the system

d$.$

The amount of physical memory currently available